Determination of component machineability in CNC manufacture

In today's global exonomy, the various components of a product are typically designed, manufactured andassembled at geographically diverse locations. During this process, computer numerically controlled (CNC) manufacturing is employed extensively in production of prismatic, cylindrical and complex metal components. In an enterprise with access to various CNC manufacturing resources, selecting suitable machines for each component is a major activity in the preliminary stages of process planning. Various techniques including tool
approach direction and visibility cone analysis are being employed to ascertain the suitability of a specific machine to manufacture a specific component. While these techniques provide the foundations for machineability determination, they are not comprehensive. Issues such as machine bed size or axis limitations are very difficult to express in terms of mathematical models and therefore it is complicated to consider these issues in the existing approaches. In this paper a novel object-oriented system for DEtermination of COmponent MAchineability (DECOMA) is designed, implemented and evaluated. DECOMA employs an ISO10303 compliant resource model and by correlating the machine data model with the product and process data models using various algorithms, determines the machineability of components on a specified machine. The product and process data are read from a STEP-NC (ISO14649) compliant file. An implementation of DECOMA using Java and an ISO14649 compliant object library is presented in the paper. The novel features of DECOMA and the unique advantages of its application are then demonstrated using test components and the representations of a number of CNC machines.